where \(a_{_0}\)  is Milgrom's constant, \(g\)  is the strength of the true gravity, and \(g_\mathrm {N}\)  is that of the Newtonian gravity. To achieve a generalization of gravity applicable in non-spherical systems, MOND requires a generalized Poisson equation derived from a Lagrangian. Two classical variants have been proposed, one with an aquadratic Lagrangian [1]}, and one with a Lagrangian making use of an auxiliary field, which is called the quasi-linear formulation of MOND [2]}. MOND may be a consequence of the quantum vacuum [3]}, [4]}, [5]}, [6]}. Reviews of MOND can be found in [7]}, [8]}.
